Boiler structure with pulverized-coal-burning furnace



Nov. 20, 1928.

G. CANTIENY BOILER STRUCTURE WITH PULVERIZED COAL BURNING FURNACE Filed Oct. 21, 1925-.

' INVENTOR 3 7' 'f ms ATTORNEY.

. Patented Nov. 20, 1928.

UNITED STATES I v 1,691,918 PATENT OFFICE."

GEORG CANTIENY, OF BERLIN, GERMANY, ASSIGNOR TO KOHLENSCHEIDUN'GS-GF- SELLSCHAIT M. B. H., OF BERLIN, GERMANY, A CORPORATION OF GERMANY.

BOILER STRUCTURE WITH PULVERIZED-COAL-BURNING FURNACE.

Application filed October 21, 1925, Serial No 63,867, and in Germany October 25, 1924.

.10 pelled to take an U-shaped path in the furnace before reaching the boiler heating surface. In such an arrangement difficulties -must be expected as the size of the furnace has to be small compared with the boiler extension and therefore the flame does not burn softly as required according to the latest new experience.

In order to avoid these difliculties it was i proposed instead of pressing the flame into 'a narrow furnace to develop same in the space between the roof-like boiler elements. This arrangement did not result satisfactorily as the up'fper boiler drums were exposed to the flame or direct contact and therefore the seams of the boiler drums were likely to be damagedfi The furnace arrangement of this'kind' is shown in German Patent No. 346,511. According to the resent invention all these difliculties are a-voi ed by a refractory arch installed below the upper boiler drums by which the flame is dividedinto two streams each of which floats through one half of the boiler and surrounds the entering mixture of coaland air thus fostering the ignition of same.

-Another object of the invention is to pro vide this refractory arch with air channels which have a plurality of openings to the 4 furnace. For this purpose the arch may be composed of two boxes advantageously supported by the front tube rows of the boiler elements. I Another object of the invention consists in connecting the first row of boiler tubes coming from the lower drum with the upper drum of the opposite boiler element in such a manner that the tubes of the first rows cross each other and form a skeleton which may supportthe boxes of the refractory arch.

Another object of the invention is introducing the coal and air in the form of flat streams having the broad extensions opposite each other and feedin supplementary air through the openings o the arch in such a manner, that the air streams flow between the flame streams thus enclosing the whole flame with fresh air nd fostering combusvaporated.

With the above and other objects in view, the invention consists in the improved water tube boiler and in the form, construction and relative arrangement of its several parts as W111 be'hereinafter more fully described, illustrated in the accompanying drawing, and subsequently incorporated in thesubjoined claims.

In the drawing wherein I have illustrated one simple and practical embodiment of my present improvements Fig. 1 represents a yertical section through the boiler structure and Fig. 2 is a fragmentary section taken on the line 2-2 of Fig. 1. Referring in detail to the drawin a designates the furnace which is placed etween the two lower boiler drums b and the lower extension of which is formed as ashpits 0. The burners d are arranged in a longitudinal row in parallel relation to the boiler drums between the hopper-like ashpits. The burners are adapted to blow the pulverized coal and air mixture in an upward direction. In. the upper part the furnace is limited by the refractory walls 6 which'are supplemented to boxes h by walls 7 and g. These boxes are connected with the furnace by a plurality of openings 2'. The refractory walls e are provided throughout their length with spaced upcomer tubes is which connect the lower boiler drums with the upper drums of the opposite boiler elements respectively. I

The other upcomer tubes m and the downcomer tubes n. connect the boiler drums with each other in the usual manner and are so arranged that there is suflicient space between them and the front tube rows k for the arrangement of the refractory boxes h, 1 0

The combustion may be observed through openings in the opposite transverse Walls of the furnace.

In the lower part of the furnace and opposite to the ashpitssuitably spaced tubes 7 of water screens are arranged which create a cooling zone between the special furnace and the ashpits in which passing therethrough the incombustible melted ash particles are cooled and granulated. The water screen tubes connect the lower boiler drums b with longitudinally arranged headers q and have a slight ascent in the water-flow direction. These headers q enclose between them the burners thus coolin same and avoiding by'their granulating e ect the covering of the burners by a layer of slag. The headers may be connected by down-comers with the upper drums of the boiler elements whereby the cooling tubes above the ashpits' are in-R serted into the water circulation of theboil er; they may also be connected with the water feeding device thus serving as feed tubes for the water to be evaporated.

According to the invention the burner nozzles have a flat cross section so as to form flame streams of little thickness whereby the small extensions of the flame surfaces are lying opposite to the evaporating surfaces of the boiler elements. Furthermore the openings in the refractory arch are arranged in such a manner that the air streams are illtroducedbetween the flame streams thus delivering additional oxygen to the whole surface of the flame streams (see Fig. 2)

The number of the air delivering openings in the arch and the downward extension of this arch may be varied according to the requirements of each installation At all events it'is possible in a very simple manner to supply the flame with suflicient supplementary air so that complete combustion may be obtained.

As it isshown in the drawing the pulverized coal and air mixture is introduced into the furnace in an upward direction by the burners. The upward flow is stopped partly by the suction in the boiler flues and partly by'the refractory arch below the upper boiler drums. Hence, the flames take a downward path surrounding the entering stream fostering the ignition of same which however substantially is effected by the radiant heat of the refractory arch. Then the gases enter the boiler in two separated streams in divergent directions. It will be seen that on the point where the flamestake a downward directed path supplementary air is admitted gradually so that a very soft and complete combustion is obtained.

The boiler structure as shown in the drawing is especially adapted to be arranged in such cases where the boiler extension must be limited as much as possible and where it is not allowed to arrange large furnaces outside the boiler. Such requirements may for instance ever exist in vessels where it is necessary to have boilers of small extensions but of great efiicacy.

While I have herein shown and described one practical embodiment of my present improvements, it will nevertheless be understood that the essential features thereof might be incorporated in various other alternative'structures, and I accordingly reserve the privilege of adopting all such changes in the form, construction and relative arrangement of the several parts as may be fairly embodied within the spirit and scope of the invention as claimed.

I claim lower part of said combustion'chamber for admitting fuel to be burned in an upward direction, cross connections between said boiler elements, a refractory arch supported by said connections, and outlets in the lower art of said combustion chamber through whlch the products of combustion pass to the boiler elements. 1 I

3. The combination with a water tube boiler formed by two separate boiler elements,

of a pulverized coal burning furnace arranged between said boiler elements, means in=the lower part of said combustion chamber for] admitting fuel to be burned in an upward direction, cross connections between said boiler elements, and a refractory arch supported by said connections and extending downwardly from the point of intersection of said cross connections, together with outlets below said arch for the products of combustion to pass from the combustion chamber over the boiler elements.

4. The combination with a water tube boiler formed by two separate boiler elements, of.

a pulverized coal burning furnace arranged between said boiler elements, means inv the lower part of said combustion chamber for admitting fuel to be burned in an upward direction, cross connections between said boiler-Q i elements, air boxes supportedby said connections, and means for admittin air from Sm boxes to the combustion cham er of the fur- 5. The combination with a water-tube boiler formed by two separateboiler elements, of

- hollow portion of the arch to the interior of a pulverized coal burning furnace arranged between said boiler elements, means in the lower part of said combustion chamber for admitting fuel to be burned in an upward direction, cross connections between said boiler elements, and refractory air boxes supported by said connections and arranged to constitute a refractory arch for the furnace.

6. The combination with a water tube boiler formed by two separate boiler elements, of a pulverized coal burning furnace arranged between said boiler elements, upwardly directed fuel delivering nozzles arrangedin a row at the bottom of said furnace, a hollow refractory arch defining the top of said furnace, air inlets for delivering air from the said furnace, and cross connections for the boiler elements comprising two rows of spaced tubes, said air inlets bein located in the space between said spaced tu )es.

7. The combination with a water tube boiler formed by two separate boiler elements upwardly converged towards each other, said boiler elements including upper andlower drums and interconnecting tubes, of a pulverized coal burning furnace arranged between said boiler elements extending downwardly into two ash hoppers, upwardly directed fuel delivering nozzles arranged between said ash hoppers and in a row in parallel relation to the boiler drums, and a refractory arch in the upper part of the furnace arranged below the upper boiler drums.

8. The combination with a water tube boiler formed by two separate boiler elements upwardly converged towards each other, said boiler elements including upper and lower drums and interconnecting tubes, of a pulverized coal burningfurnace arranged between said boiler elements extending downwardly into two ash hoppers, upwardly directed fuel delivering nozzles arranged between said ash hoppers and in a row in parallel relation to the boiler drums, and a refractory arch in the upper part of the furnace arranged below the upper boiler drums, said arch being provided with openings and means for delivering supplementary air therethrough into'the furnace.

In testimony whereof I afiix my signature.

GEORG CANTIENY. 

